Where Marijuana Plants Flourish Under Energy-Saving LED Lights

Behind the covered windows of a nondescript two-story building near the Olympia Regional Airport, hundreds of marijuana plants were flowering recently in the purple haze of 40 LED lights.

It was part of a high-stakes experiment in energy conservation — an undertaking subsidized by the local electric company. With cannabis cultivation poised to become a big business in some parts of the country, power companies and government officials hope it will grow into a green industry.

The plants here, destined for sale in the form of dried flowers, joints or edible items, were just a few weeks from harvest and exuding the potent aroma of a stash room for the Grateful Dead. But the energy-efficient LED lights were the focus of attention.

“We wanted to find a way to save energy — that was important to us,” said Rodger Rutter, a retired airline pilot who started this indoor pot-farming business, Evergrow Northwest, after Washington State legalized recreational cannabis in 2012.

“We wanted to be able to offer the best product at the best price,” Mr. Rutter said, “and a big part of the cost is energy.”

As cannabis has increasingly gone legitimate — about two dozen states had already legalized it in some form before several others eased restrictions on Election Day — electric utilities have struggled to cope with the intensive energy demands of the proliferating industry.